Much recent effort has been directed towards the development of economically viable methods for fabricating films of metal oxides and particularly films of multicomponent metal oxides, i.e., metal oxides containing more than one type of metal in the chemical composition of the film. Among the various methods employed are physical-based vapor deposition methods such as laser ablation or evaporation, of magnetron sputtering, and electron beam evaporation, chemical-based vapor deposition methods such as spray pyrolysis, and conventional chemical vapor deposition.
The properties of the multicomponent metal oxide films preferably include a highly smooth mirror-like surface, a uniform or consistent chemical composition or stoichiometry, a conformal deposition, i.e., a uniform coating thickness upon either a planar or a non-planar substrate surface, and a crystallographic orientation upon the substrate. Also, the method of depositing such multicomponent metal oxide films preferably has a high rate of deposition.
Each of the presently available deposition methods has drawbacks that limit the usefulness of the particular method in deposition of multicomponent metal oxide films. For example, laser evaporation, rf magnetron sputtering, and spray pyrolysis do not produce a highly smooth mirror-like surface on non-planar substrates. Conventional chemical vapor deposition utilizes a number of precursor compounds that can volatilize and decompose at different rates and therefore does not produce a uniform composition. Rf magnetron sputtering and electron beam evaporation do not produce consistent film compositions. Further, none of the physical-based vapor deposition methods can typically achieve conformal coatings on non-planar surfaces as such methods are generally limited to line-of-sight deposition.
Accordingly, one object of this invention is to provide a process of depositing a film of a multicomponent metal oxide having a highly smooth mirror-like surface.
A further object of this invention is to provide a process of depositing a film of a multicomponent metal oxide having a consistent chemical composition or stoichiometry.
Yet another object of this invention is to provide a process of depositing a conformal film or coating of a multicomponent metal oxide onto either a planar or a non-planar substrate.